Well yes, maybe "ethical" wasn't the best word, lol, but it seems that in the Q Continuum "lexicon" (hopefully better) it looks like there could be a few "don'ts" for their membership. After all, Q Sr. was suspended from his powers in TNG episode "QWho" for his previous actions, so even for those superior beings, there are maybe some sort of limit, however vague, to what they are overall allowed to do in the universe.